Principal Penetration Tester

Do you want to be at the forefront of protecting our society against cyber threats? We are looking for a Principal Penetration Tester to team up with the most dedicated team of cyber specialists in our Offensive Security team.

About Truesec – A Leading Cybersecurity Company

Since 2005, Truesec has been a native cybersecurity company, driven by one single purpose: Creating safety and sustainability in a digital world by preventing cyber breach and minimizing impact.

Over the years, we’ve earned the trust of organizations worldwide and gained a strong reputation internationally. Our team consists of dedicated specialists covering the entire spectrum of cybersecurity – with capabilities in Predict, Prevent, Protect, Respond, and Recover.

Today, we employ around 350 employees – and as cybercrime grows, we need to grow. To support that goal, we are now looking for a Principal Penetration Tester who wants to make a difference in our Offensive Security Team.

Offensive Security Team

Truesec’s Offensive Security Team is a group of dedicated cybersecurity specialists working proactively to help organizations protect themselves against cyber breaches by identifying vulnerabilities before they are exploited. As part of this team, you’ll collaborate closely with some of the world’s top security experts, leveraging combined knowledge and experience to conduct penetration tests, security assessments, and advanced red and purple team engagements. 

The work is highly technical and focuses on uncovering security weaknesses in enterprise- and cloud environments, including mobile applications, cloud platforms, IOT/OT systems, and both Linux and Microsoft infrastructures. Team members lead assignments from start to finish, maintaining direct contact with customers and driving projects alongside colleagues, all with the shared mission of making a real difference in cybersecurity and contributing to a safer digital world

About the Role

This is a unique opportunity to become the very first member of Truesec’s Offensive Security team in Finland, pioneering our proactive cybersecurity initiatives and shaping the future of offensive security in the region

As a Principal Penetration Tester within Truesec’s Offensive Security Team, you will be at the forefront of protecting organizations against advanced cyber threats. This is a unique opportunity to work alongside some of the world’s most dedicated and talented cyber specialists. You will lead and deliver highly complex offensive security engagements—ranging from advanced penetration tests to red and purple team exercises—across enterprise environments, cloud platforms, and specialized domains such as IOT/OT.

Your role extends beyond technical execution: you’ll shape strategic initiatives, guide and mentor teams, and make high-level decisions that influence both Truesec’s direction and our clients’ long-term cyber resilience. You will own key customer deliveries from start to finish, navigate complex and undefined challenges, and continuously develop tools, processes, and solutions critical to our ongoing success. As a Principal, you serve as a guiding star—demonstrating best practices, fostering collaboration, and ensuring projects remain focused and impactful.

Your Background

• At least 7+ years of experience in offensive security, penetration testing, or related fields.

• Recognized as a subject-matter expert with deep and broad expertise across multiple platforms, technologies, and methodologies.

• Proven track record of leading highly complex security assessments and offensive engagements.

• Experience managing critical customer projects, mentoring teams, and contributing to the development of new tools, processes, or services.

• Passion for cybersecurity, continuous learning, and a genuine desire to make a difference for clients and the wider community.

Required Skills

You should meet most of the following requirements, or be a true expert in several:

• Extensive experience in penetration testing of enterprise environments.

• Deep knowledge of identifying vulnerabilities in both Windows and Linux systems.

• Advanced skills in network-based penetration tests, credentials extraction, and lateral movement.

• Expertise in penetration testing of mobile applications, IOT/OT systems, and cloud environments (e.g., AWS, Google Cloud, Microsoft Azure).

• Ability to present complex findings to both technical and non-technical audiences, including C-level stakeholders.

• Strategic mindset with the ability to make decisions affecting business direction and customer outcomes.

• Experience in leading projects and mentoring colleagues.

Bonus skills

• Sysadmin background or experience managing large-scale IT environments.

• Ability to understand and work with multiple programming languages.

• Full proficiency in at least one programming language.

• Experience with code-assisted/code review-based penetration testing.

• Relevant security certifications (e.g., OSCP, OSCE, CISSP, GIAC).

• Active participation in the offensive security community (e.g., speaking at conferences, contributing to forums or open-source projects).

Due to the sensitivity in our assignments, we require Finnish citizenship, citizenship in an EU country, or a Finnish work permit.

Join Our Mission Toward a Safe Digital Future

At Truesec, you will help shape the future of offensive security while working with and learning from some of the industry’s best minds. You’ll have the freedom and responsibility to drive innovation, mentor the next generation of cybersecurity talent, and make a tangible impact for our clients and society at large. If you are ready to lead, inspire, and deliver at the highest level, we are excited to get to know you.

Apply for this job